Color printing systems are widely used for a variety of applications. For example, color printing systems are used in office environments, print shops, etc.
Throughout the life cycle of a color printing system, modifications will be made to a printing system. These modifications can occur during the development phase, the installation phase and/or after the color printing system has been released to the customer.
As modifications are made to a printing system it can be difficult to maintain a consistent color rendering from one point in time to the next. Maintaining consistent color rendering is particularly important after a color printing system has been released to a customer and the system color changes need to be minimized.
A particularly challenging situation is when substantial modifications have been performed on a print engine or on its associated DFE (Digital Front End). It is often observed that systems use different sets of profiles or different system settings, relative to the original printing system, to perform required color transformations. This situation is common, especially for systems with multiple controls and rendering intent processes which reflect some way of preferred rendering such as a ‘perceptual’ rendering intent, ‘relative calorimetric’ intent, or a ‘saturation’ rendering intent. Such rendering intents are often controlled by editing the profile or modifying the parameters of a LUT (Look Up Table) generation program until a satisfactory print image is obtained. Additional rendering parameters, such as gray component replacement (GCR), or under color removal (UCR) can also be causes of changed system behavior.
One way of quantifying color differences is by performing measurements on printed patches of specific colors. The measurements will indicate whether or not the color rendering of a color printing system has changed relative to a reference set of measurements. However, performing measurements of printed patches will not conclusively establish what has been modified in the event the color rendering has changed. For example, a change in color rendering could be a result of print engine drift, DFE modifications and/or other system variations. Moreover, the process of measuring the color rendering properties of printed patches utilizing instrumentation can be time consuming and cumbersome.
This disclosure provides a system and method to assess whether the color rendering of a color printing system has been modified. In addition, the disclosure provides a system and method to determine if any color rendering changes are attributable to the DFE, print engine, workflow etc.